The proposed research assesses the effectiveness and impact of a national telephone cancer information program (the Cancer Information Service), a program of the National Cancer Institute. The goals of the research are: (1) to examine the effects of cancer information provided through toll-free telephone lines on health knowledge, attitudes and behavior and on the diffusion of information, (2) to evaluate the accessibility, utilization, and quality of the CIS program, (3) to study the acceptibility of the CIS in providing timely, up-to-date, and accurate cancer information to the public, and (4) to explore alternatives to the current policies and practices of the CIS in an effort to improve upon program delivery, organization, and performance. To achieve these goals, a subset of CIS callers (i.e., those people who are undiagnosed and symptomatic who have not been to a physician) will be surveyed and interviewed about a wide range of issues ranging from an evaluation of their call to the CIS to the actions they took as a result of their call. Between 600-1000 people will be studied. These effects of the CIS will be assessed at two times, the first to measure short-term effects (one month after the initial CIS call) and the second to measure longer range effects (three to four months after the initial CIS call). In addition, a post-call letter of reinforcement will be sent to half the sample within a few days of their call to examine the efficacy of simple reinforcement on health-related outcomes. Currently, the CIS does not send out such letters. The survey and interview data will be supplemented by various sources of data currently collected by the program in order to obtain a comprehensive and accurate assessment of program impact. The data will very likely contribute both to applied and to theortical issues.